pNPP Substrate

p-Nitrophenyl Phosphate (pNPP) is the preferred substrate of ALP-based microwell plate assays. In the presence of Alkaline phosphatase (ALP), pNPP is hydrolysed into p-nitrophenol and inorganic phosphate, which results in a yellow, soluble end product. The result is measured at 405 nm (kinetic assays). The reaction can be stopped by adding an equal amount of 1M Sodium Hydroxide solution and the result is read at 405 nm. The intensity of the yellow colour is directly proportional to the concentration of the reactant.

The general approach to supplying pNPP substrates has been to provide customers with pNPP tablets or powder and a substrate buffer. The customer would have to make up the solution themselves, adding an additional preparation step. These solutions were also only stable for a short period of time.

Biopanda's pNPP substrates are highly active and stable, supplied in a ready-to-use mono-component format for use in ALP-based EIA. Its general features are: